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[2003:cb:c703:c100:c136:f914:345f:f5f3]) by smtp.gmail.com with ESMTPSA id e4-20020adfdbc4000000b00228c792aaaasm13288512wrj.100.2022.09.19.02.20.13 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 19 Sep 2022 02:20:14 -0700 (PDT) Message-ID: <93c044ca-7d2f-e23f-8eb4-72c133737a15@redhat.com> Date: Mon, 19 Sep 2022 11:20:13 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.2.1 Subject: Re: [PATCH -v2] lib/notifier-error-inject: fix error when writing errno to debugfs file To: Akinobu Mita , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, corbet@lwn.net, osalvador@suse.de, shuah@kernel.org, Zhao Gongyi , Wei Yongjun , Yicong Yang References: <20220917071427.28499-1-akinobu.mita@gmail.com> From: David Hildenbrand Organization: Red Hat In-Reply-To: <20220917071427.28499-1-akinobu.mita@gmail.com> X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1663579219; a=rsa-sha256; cv=none; b=ZLg5xMw7VXRqDaOS5KHTQVcFScOdbDgbYKIFlltbcbNnCK3tq1tdxav93o34DleGCe/TWM 0m6PHHYJycyW98GjKPo4RsbAewjP5eEECuabsjo5nezOXbWytNNtBDnm+6EpKxgRkd9MXH io7fqMRotZUT2shbWZV1N8zKQfJ8d0I= ARC-Authentication-Results: i=1; imf03.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=djzI4BjG; spf=pass (imf03.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1663579219; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=VrBD4wlaONcMGYg1HxtJ7UDDQW/eU0hoafM/vqbQdC8=; b=lYC+ZART9TMaMpBy84CvXB0XeQ2Gijp7ljB3NH9rW4nVlFUBC4SpZfMiNXK0r+v0FLWgb+ ctOsrBoK7GW2ZwH2pznAtVHlhRRqfjUumaRmACWHhVYy1+5M7DVuP/GTClTCMdp3nlURbb 9TwFtOPdx6YLsqzsBzkO6tcCStY9zI4= X-Rspamd-Queue-Id: CC7A7200A5 X-Rspamd-Server: rspam05 X-Rspam-User: Authentication-Results: imf03.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=djzI4BjG; spf=pass (imf03.hostedemail.com: domain of david@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=david@redhat.com; dmarc=pass (policy=none) header.from=redhat.com X-Stat-Signature: fbq54kw4zqqyx7uw4nr5dkdrb73n5mz8 X-HE-Tag: 1663579219-73117 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On 17.09.22 09:14, Akinobu Mita wrote: > The simple attribute files do not accept a negative value since the > commit 488dac0c9237 ("libfs: fix error cast of negative value in > simple_attr_write()"), so we can no longer use DEFINE_SIMPLE_ATTRIBUTE() to > define a file operations for errno value. > > Fixes: 488dac0c9237 ("libfs: fix error cast of negative value in simple_attr_write()") > Reported-by: Zhao Gongyi > Signed-off-by: Akinobu Mita But shouldn't we fix simple_attr_write() instead? I mean, simple_attr_read() might use attr->fmt to print a signed value, but simple_attr_write() fails on signed values now? I might be wrong, but there is a disconnect. I feel like simple_attr_write() should similarly make decisions based on attr->fmt. > --- > v2: Fix Reported-by line > > lib/notifier-error-inject.c | 38 ++++++++++++++++++++++++++++++------- > 1 file changed, 31 insertions(+), 7 deletions(-) > > diff --git a/lib/notifier-error-inject.c b/lib/notifier-error-inject.c > index 21016b32d313..30ec41f58d53 100644 > --- a/lib/notifier-error-inject.c > +++ b/lib/notifier-error-inject.c > @@ -3,20 +3,44 @@ > > #include "notifier-error-inject.h" > > -static int debugfs_errno_set(void *data, u64 val) > +static int notifier_err_errno_show(struct seq_file *m, void *data) > { > - *(int *)data = clamp_t(int, val, -MAX_ERRNO, 0); > + int *value = m->private; > + > + seq_printf(m, "%d\n", *value); > + > return 0; > } > > -static int debugfs_errno_get(void *data, u64 *val) > +static int notifier_err_errno_open(struct inode *inode, struct file *file) > { > - *val = *(int *)data; > - return 0; > + return single_open(file, notifier_err_errno_show, inode->i_private); > +} > + > +static ssize_t notifier_err_errno_write(struct file *file, const char __user *ubuf, size_t len, > + loff_t *offp) > +{ > + struct seq_file *m = file->private_data; > + int *value = m->private; > + int ret; > + > + ret = kstrtoint_from_user(ubuf, len, 0, value); > + if (ret) > + return ret; > + > + *value = clamp(*value, -MAX_ERRNO, 0); > + > + return len; > } > > -DEFINE_SIMPLE_ATTRIBUTE(fops_errno, debugfs_errno_get, debugfs_errno_set, > - "%lld\n"); > +static const struct file_operations fops_errno = { > + .owner = THIS_MODULE, > + .open = notifier_err_errno_open, > + .read = seq_read, > + .write = notifier_err_errno_write, > + .llseek = seq_lseek, > + .release = single_release, > +}; > > static struct dentry *debugfs_create_errno(const char *name, umode_t mode, > struct dentry *parent, int *value) -- Thanks, David / dhildenb